The present invention relates to a control system for carrying out the switching control of an electrical circuit a second piece of equipment by means of a digital signal in a first piece of equipment.
Until now, (n+1) wires or contacts are needed including the ground wire in order to connect equipment A to equipment B when n of the circuit groups in the equipment are changed over or driven by means of a digital signal source of n bits or n switch groups in the equipment A of the two pieces of equipment A and B connected to each other.
On the other hand, along with the increase of the number of wires or number of connectors between the two pieces of equipment it is likely that the manufacturing processes will be increased so as to increase the manufacturing cost while the reliability is decreased, which is not advantageous.
Until now, in order to decrease the number of wires between two pieces of equipment parallel digital signals are converted into serial signals for example by a time-sharing system and then transmitted.
In this way, it is sufficient to provide such signals on a transmission line excluding the ground wiring, whereby in case of this time sharing system it is necessary to prepare a complicated circuit construction in order to provide necessary timing, while a time delay necessarily takes place because parallel signals are once converted into serial signal and again into parallel signals. Accordingly some problem often takes place when the number of the bits of the digital signal to be transferred is increased.
The present invention has been made in consideration of the above mentioned background.